1,720,977 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Overview of NPPs Component Reliability Data Collection with Regards to Time-dependent Reliability Analysis Applications - EC JRC Network on Use of Probabilistic Safety Assessments (PSA) for Evaluation of Aging Effects to the Safety of Energy Facilities - Task 4
Full text linkThis report presents the state of the art of existed NPPs component reliability data collection systems which aimed to elaborate components reliability parameters to be used in Probabilistic Safety Assessements (PSA). A specific emphasis was done to the possible application of data in time-dependent reliability analysis.
The report was prepared by JRC IE in the frame of EC JRC Ageing PSA Network Task 4 activities and is based on analysis of responses of Network participants to the questionnaire.
Main conclusions and recommendations are presented in the report and they addressed to the data availability and accessibility, as well as to possible improvements of data collection and important issues to be considered in Ageing PSA Network work plan.JRC.F.4 - Nuclear design safet
PSA as a Tool for Evaluation of Aging Effects to the Safety of NPPs
No full textThe paper summarizes the results of research studies and discussions on the use of PSA to
evaluate the SSC ageing effect on overall plant safety carried out within the framework of the ECJRC
Ageing PSA Network.
In particular, statistical methods and approaches to identify and model ageing effects on
safety component reliability using operating experience data are presented. The possible impact of
agerelated
degradation on the component reliability and on the plant risk profile is demonstrated
using the PWR Large LOCA PSA model as an example. Practical insights, recommendations and
limitations are also discussed.
Key Words: ageing effects, Probabilistic Safety Assessment, timedependent
reliability
model.JRC.F.4 - Safety of future nuclear reactor
Consideration of NPP Systems Structures and Components Ageing Effects in Probabilistic Safety Assessments
No full textThe Thesis presents the results of research studies on the use of PSA for evaluation of SSC aging effect to the overall plant safety carried out in the frame of EC JRC Network activities on Incorporating Ageing Effects into Probabilistic Safety Assessment (Aging PSA).
The basic concern to use the PSA for aging evaluation is coming from the requirement to accomplish the safety goals during the whole lifecycle of the nuclear installation (including the extended lifetime). In probabilistic terms, INSAG-12 specifies a safety goal as follow :
The target for existing nuclear power plants consistent with the technical safety objective is a frequency of occurrence of severe core damage that is below about 10�4 events per plant operating year. Severe accident management and mitigation measures could reduce by a factor of at least ten the probability of large off-site releases requiring short term off-site response.�
So, for the units which approach to the end of initial design lifetime and especially for those which planned to extend the lifetime, it has to be demonstrated that the plant safety level, at least, will be remain in accordance with this target till the end of operation.
Additional motivation to use the PSA for aging assessment proceeds from the significant limitations of deterministic approach and needs to prioritize the Aging Management or Life Extension actions to maintain established safety goals.
Objectives of the Thesis are
- to show what PSA tasks have to be addressed and performed to take into account aging effects and to demonstrate their impact to the overall plant safety,
- define the new approaches needed and priority for their development and demonstration.
PSA could be used as a tool for safety assessments of aged NPPs, in order to do that the the following steps have to be done :
- review of PSA scope and assumptions,
- identify components susceptible for aging by using risk importancy, analyzis of aging trends and qualitative analysis of ageing effects,
- elaborate age-dependent reliability models,
- introduce them into PSA (consider, where necessary, test and maintenance effectiveness and periodicity),
- perform time dependent quantifications and sensitivity analysis.
The study presents an approach and detailed procedures how to do that with some examples of application.
The Thesis was conducted in the frame of EC JRC Ageing PSA Network activities under the Collaboration Agreement with Obninsk State University for Nuclear Engineering (IATE).JRC.F.5 - Safety of present nuclear reactor
A Case Study on Incorporation of Ageing Effects into the PSA Model
Full text linkThis report presents the results of a case study on incorporation of ageing effects into the PSA model and discussions on the use of PSA to evaluate the SSC ageing effect on overall plant safety. The study was carried out within the framework of the EC-JRC Ageing PSA Network Task 7.
The possible impact of age-related degradation on the component reliability and on the plant risk profile is demonstrated using the PWR Large LOCA PSA model as an example. Practical insights, recommendations and limitations are also discussed.JRC.F.5 - Safety of present nuclear reactor
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